The present invention relates to polyethylene filaments and their production. More particularly, it relates to polyethylene filaments having high strength and modulus with excellent heat resistance and size stability, and their production.
Polyethylene filaments have various advantageous properties and are useful as industrial materials. Namely, they are of light weight, good strength, excellent resistance to chemicals such as acid and alkali and low cost. However, their heat resistance and size stability are not sufficient. Further, enhancement of strength and modulus is desired for expanding the area of their use.
Hitherto, it is known to subject polyethylene filaments obtained by melt spinning to irradiation with radioactive rays for crosslinking. It is also known to subject the polyethylene filaments to graft polymerization with acrylic acid thereon under irradiation with radioactive rays. These procedures are said to be effective in improvement of heat resistance. However, the improvement of heat resistance by those procedures is not sufficient. Further, any material increase in strength is not produced by the procedures.